Beading-key for traverse-tables



R. S. BLITZ.

READING KEY FOR TRAVERSE TABLES.

APPLICATION FILED IAILZQ, 1916.

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TRAVERSE TABLES COSINE.

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A TTORNEYS R. S. BLITZ.

READING KEY FOR TRAVERSE TABLES.

APPLICATION FILED IAR.29. 1916.

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READING-KEY FOR TRAVERSE-TABLES.

Specification of Letters Patent. Patented Aug, 22, 1916.

Application fll'ed March 29, 1916. Serial no. 87,471.

To all whom it may concern Be it known that I, RALPH S. BLITZ, a citizen of the United States, and a resident of Butte, in the county of Silverbow and State of Montana, have invented a new and Improved Reading-Key for Traverse-Tables, of which the following is a full, clear, and exact description.

The object of the invention is to provide a new and improved reading key for use on traverse tables to enable a surveyor or other person to readily and accurately read horizontal and vertical distances or latitude and departure according to the problem in hand.

In order to produce the desired result, use is made of a key in the form of a plate provided with a column graduation having its marks spaced apart corresponding to the columns of a. traverse table, and an indicator movable on the said plate and adapted to indicate on the marks of the said graduation and adapted to position the reading key on the traverse table.

A practical embodiment of the invention is represented in the accompanying drawings forming a part of this specification, in which similar characters of reference indicate corresponding parts in all the views.

Figure 1 is a plan view of the reading key as applied to one of Gurdens traverse tables; Fig. 2 is a plan view of the reading key; Fig. 3 is a cross section of the same on the line 33 of Fig. 2; Fig. 4 is a plan view of a modified form of the reading key; and

Fig. 5 is a cross section of the same on theline 55 of Fig. 4.

The reading key is in the form of a rectangular plate 10 of celluloid, hard rubber,

or other suitable material, and on the face of the plate 10 adjacent the opposite edges are arranged graduations 11 and 12 consecutively numbered from zero to 9 with the marks spaced apart to correspond to the columns of a traverse table. The graduation 11 is provided at the ends with spots 13 and 14, and similar spots 15, 16 are arranged at the ends of the graduation 12, but 1 the spots 13 and 14: are differently colored from the spots 15 and 16, that is, the spots 13 and-14 are preferably made black while the spots 15 and 16 are colored red. Ad-

jacent the spots 13 and 14 are legends 17' and 18, reading Sine 0 to 45 and Cosine 0 to 45, and similar legends 19 and 20 are arranged admcent the spots 15 and 16 and reading Sine 45 to 90 and Cosine 415 to 90?. The plate 10 is provided with a guideway 25, preferably arranged at the middle of the plate, as indicated in Figs. 1, 2 and 3, but the said guideway may be arranged at the edges, as shown in Fig, 5. On the guideway 25 is mounted to slide an indicator 26 having a knob 27 for conveniently moving the indicator along the guideway 25 in the direction of the length of the plate 10. The indicator 26 is in the form of a transverse strip of sheet metal or other material, and is provided with apertures 28, 29 registering with the marks of the graduations 11 and 12. The indicator 26 is provided at its ends with pointers 30 and 31 in transverse alinement with the centers of the apertures 28 and 29. As shown in Figs. 4 and 5, the pointers are in the form of transverse lines.

The reading key is designed for use on the well known Gurdens traverse tables calculated to single minutes and to 100 of distance. The traverses are given to four places of decimals so that the sines and cosines for a distance of twelve miles can be ascertained correctly to within half an inch. As shown in Fig. 1, the angles 0 to 45 are given at the top of the page, and angles of 45 to 90 at the foot, while the distances 1 to 100 are in the opposite columns, and the quantity sought is found at the intersection of the column containing the required angle and the line on which is the required distance. Each traverse table A is divided by a central line B into left and right-hand portions, and the columns C and C adjacent the center line B give the whole numbers, while the decimal quantities increase from the said columns toward the edge of the page, the sines increasing to the right and the cosines to the left.

Presuming that the following problem is to be solved with the aid of the reading key, namely, the vertical angle:35 32, slope distance=185.39 ft., and the horizontal and vertical distances are required: The user of the key first shifts the indicator 26 along the guideway 25 until-the aperture 28 discloses the numeral 2 of the graduation 11,; as'shown in Fig. 1. It is understood that the indicator is set over the numeral 2 as this is the last numeral in the minutes'of the angle given. The operator next turns to table 214 of Gurdens traverse tables and 39 thus including the angle 35 32' of the problem above mentioned. The plate 10 is now placed on the transverse table with the pointers 30 and 31 in register with the center line ]B of the table A and with the plate 10 extending sidewise of the table, as shown in Fig. 1. As the slope distance is given in the problem as 185.39 feet this amount is divided'into 100 feet, 85 feet and .39 feet. In order to find the horizontal distance and the vertical distance for 100 feet, the plate 10 is first placed at the bottom of the page, as indicated in dotted lines inFig. 1, and with the upper edge of the plate 10 under the bottoms of the columns immediately be low the numerals 100 in the distance columns at the sides of the table. It will now be noticed that this bottom line shows to the left of the line B the numeral 81, and opposite the spot 14 the numeral..377 8, thus giving 81.3778 as the horizontal distance for 100 feet. In the same manner, the first column to the right of the center line B. shows the numeral 58 and the column opposite the spot 13 shows the numeral .1177, thus making a total of 58.1177 for the vertical distance of 100 feet. The plate 10 is next shifted upward on the table until the upper edge registers with the numerals 85 in the outside distance columns, as shown in full lines in Fig. 1, and the operator can now readily read in the column C the numeral 69, and

opposite thespot 14 the numeral .1711, thus 7 giving 69.1711 as the horizontaldistance for 85 feet, and in the column C the operator reads the numeral 49, and opposite the spot 13 the operator finds the numeral .4000, thus giving 49.4000 as the vertical distance for 85 feet. The operator next shifts the plate 10 farther upward on the table A until the upper edge of'the plate registers with the distance .39, as'indicated in dotted lines in Fig. 1, and the operator can now read in the columnfi the numeral -.31, and opposite the spot 14 the numeral .7373, thus giving .317373 as the horizontal distance for .39 feet, and in the column C the operator finds the numeral .22 and opposite the spot 13 the numeral .6659, thus glving .226659. as the vertical distance for .39 feet. The several figures are noted down as read by the operator thus producing the following result: 1

(foams. Sine.

Thus thevanswer is 150187 feet for horizontal distance and 107.74 feet for vertical distance. If the angle exceeds 45 then the plateis turned around and used in practically the same manner as above described for finding either horizontal and vertical 1,1es,77a

'- distances or latitude and departure. When the plate is turned around then the graduation 12 with the spots 15, 16 and the legends 19, 20' are uppermost, and the reading key is then used practically in the same manner as above described. Thus to find latitude and departure, in case the problem is course N. 55 37 W., and the horizontal distance 89.23 feet, then the indicator 26 is set until the aperture 29 registers with the numeral 7 of the graduation 12, it being understood that the numeral 7 is the last one of the 'minutes in the problem. The operator now proceeds as before, remembering, however, that all angles above 45 appear on the bottom of the page and the sine and cosine are reversed in position. The operator uses the reading key for the .problem given on table 207 of Gurdens traverse tables, and which table 207 shows the angles 55 31 up to 55 40'. Noting down the various numerals obtained, the problem resolves itself as follows Cosine. saw.

7 bles, and the user of this reading key can turn out considerably more work than with the old mode of procedure of running down the columns with the fingers.

Having thus described m invention, I claim as new and desireto secure by Letters Patent:

1. A reading key for traverse tables, comprising a plate provided with. a column graduation having its marks spaced apart one edge of the said plate and having consecutively numbered marks corresponding to the columns of a traverse table, legends indicating the sine 0 to 45 and the cosine of 0 to 45 and associated with the said column graduation, a second column graduation along the other edge of the plate and 7 having consecutively numbered marks corresponding to the (columns of a raduation table, legends indicating the sine o 45-to 90 and the coslne of 45 to 90 and associated with the said second column graduation, and

an indicator slidable on the said plate and having means adapted to register with the said marks of both graduations and having means for positioning the reading key on the traverse tables.

3. A reading key for traverse tables, comprising a plate, a column graduation along one edge of the said plate and having consecutively numbered marks corresponding to the columns of a traverse table, le ends indicating the sine 0 to 45 an the cosine of 0 to 45 and associated with the said column graduation, a second column graduation along the other edge of the plate and havin consecutively numbered marks correspondlng to the columns of a graduation table, legends indicating the sine of 45 to 90 and the cosine of 45 to 90 and associated with the said second columngraduation, and an indicator slidable on the said plate and having apertures adapted to register with the said marks of both graduations and having pointers adapted to register with the center line of a traverse table to position the reading key on said table.

4. A reading key for traverse tables; comprisin a plate, a column graduation along one e ge of the said plate and having consecutively numbered marks corresponding to the columns of a traverse table, legends indicating the sine of 0 to 45 and the cosine of 0 to 45 and associated wit-h the said column graduation, a second column graduation along the other edge of the plate and having consecutively numbered marks corresponding to the columns of a graduation table, legends indicating the sine of 45 to 90 and the cosine of 45 to 90 and associated with the said second column graduation and difi'erently colored spots on the ends of the said column graduations, and an indicator slidable on the said plate and having means adapted to register with the said marks of both graduations and having means for positioning the reading key on the traverse table.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

RALPH s. BLITZ.

Witnesses:

J. H. MANwARrNG, G. D. WATSON. 

